The effects of newly formed synthetic peptide on bone regeneration in rat calvarial defects

Abstract

Purpose: Significant interest has emerged in the design of cell scaffolds that incorporate peptide sequences that correspond to known signaling domains in extracellular matrix and bone morphogenetic protein. The purpose of this study was to evaluate the bone regenerative effects of the synthetic peptide in a critical-size rat calvarial defect model.

Methods: Eight millimeter diameter standardized, circular, transosseus defects created on the cranium of forty rats were implanted with synthetic peptide, collagen, or both synthetic peptide and collagen. No material was was implanted the control group. The healing of each group was evaluated histologically and histomorphometrically after 2- and 8-week healing intervals.

Results: Surgical implantation of the synthetic peptide and collagen resulted in enhanced local bone formation at both 2 and 8 weeks compared to the control group. When the experimental groups were compared to each other, they showed a similar pattern of bone formation. The defect closure and new bone area were significantly different in synthetic peptide and collagen group at 8 weeks.

Conclusions: Concerning the advantages of biomaterials, synthetic peptide can be an effective biomaterial for damaged periodontal regeneration.

Keywords: Bone regeneration; Collagen; Synthetic peptide.

Figure 1

Schematic drawings of calvarial osteotomy defect showing histomorphometric analysis.

Figure 2

Control group at 2 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving control at 2 weeks post-surgery. At 2 weeks, the augmented area was covered with dense connective tissue. Minimal new bone formation was observed.

Figure 3

Control group at 8 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving control at 8 weeks post-surgery. At 8 weeks, more bone formation was observed in the base when compared to 2 weeks.

Figure 4

Collagen alone group 2 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving collagen only at 2 weeks post-surgery. The defects were filled with loose or dense, fibrous connective tissue and limited new bone formation was observed at the defect margin at 2 weeks.

Figure 5

Collagen alone group at 8 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving collagen only at 8 weeks post-surgery. The resorption of collagen progressed extensively. There was an increase in bone volume and there was no invagination of the peripheral tissue.

Figure 6

Synthetic peptide alone group at 2 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving synthetic peptide only at 2 weeks post-surgery. There was almost no resorption and there was slight new bone formation, a slight increase in volume as well.

Figure 7

Synthetic peptide alone group at 8 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving synthetic peptide only at 8 weeks post-surgery. There was a great deal of resorption. The new bone formation increased compared to the 2-week group. Osteoblast-like cells and a very few giant multinucleated cells could be detected in the periphery of the margin whereas the center showed almost no new bone formation.

Figure 8

Synthetic peptide in collagen carrier group at 2 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving synthetic peptide and collagen only at 2 weeks post-surgery. There was not much bone regeneration or defect closure.

Figure 9

Synthetic peptide in collagen carrier group at 2 weeks (H&E stain, ×50) representative photomicrographs of defect sites receiving synthetic peptide and collagen only at 2 weeks post-surgery. There were no osteoblast-like cells detected.

Figure 10

Synthetic peptide in collagen carrier group at 8 weeks (H&E stain, ×20) representative photomicrographs of defect sites receiving synthetic peptide and collagen only at 8 weeks post-surgery. At 8 weeks post-surgery, new bone formation was moderate. There was loose connective tissue formation around the defect area and there was no infiltration of inflammatory cells. Collagen was almost resorbed.

Figure 11

Synthetic peptide in collagen carrier group at 8 weeks (H&E stain, ×50) representative photomicrographs of defect sites receiving newly formed synthetic peptide and collagen only at 8 weeks post-surgery. There was loose connective tissue formation around the defect area and there was no infiltration of inflammatory cells. The defect area has been replaced by a parallel pattern of connective tissue.